Electric welding torch



Oct. 20, 1942. s. L. CASNER ELECTRIC WELDING TORCH Filed Oct. 28, 1940 ATTORNEY Patented Oct. 20, 1942 UNITED STATES PATENT OFFICE 2,299,679 ELECTRIC WELDING TORCH Burton L. Casner, Hoboken, N. J. Application October 28, 1940, Serial No. 363,097

Claims.

factory in performance, they have a number of disadvantages among which is the limitation that they are not readily portable because they cannot be far separated from the source of combustion material, usually heavy and cumbersome high-pressure gas tanks. On the other hand, electric welding torches, as contrasted to electric welders utilizing consumable welding electrodes, have occasionally been proposed in the prior art. However, such torches have not been commercially acceptable since, in general, the arc formed thereby flares out over a wide area, which is undesirable both because it tends to heat too large a portion of the work and because it is not suillclently intense to perform many cutting and welding operations.

It is an object of the present invention, therefore, to provide an improved electric welding torch eilective to develop an intense, concentrated, point-like arc.

It is a further object of the invention to provide an improved electric welding torch of the type described in which the arc is concentrated into a point and is stable under all working conditions.

In accordance with the invention, there is provided an electric welding torch comprising a supporting member and a pair of electrode holders supported thereby and adaptedto hold a pair of current-carrying electrodes at an angle to each other and in arc-forming position. There is disposed within the angle of the normal electrode positions a first magnetic means for forming a magnetic field transverse to the normal path of the arc to extend it away from the torch, while other magnetic means are disposed outside the angle of the normal electrode positions for developing a magnetic field in the region of the arc to concentrate the are into substantially a point.

In accordance with another feature of the invention, a pair of substantially parallel rods are supported from the supporting member and the electrode holders are individually supported by the rods, one of the rods being longitudinally adjustable relative to the other to adjust the electrodes to strike, control or extinguish the arc, and there is provided resilient means for biasing the adjustable rod to a position effective to extinguish the arc.

For a better understanding of the invention,

together with other and further objects thereof,

reference is bad to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring now to the drawing, Fig. l is a view in side elevation, partly-broken away, of an improved welding torch embodying the present invention; Fig. 2 is a detailed cross-sectional view of a preferred form of the magnets included in the torch of Fig. 1;' while Figs. 3a and 3b are schematic diagrams illustrating the nature of the magnetic fields developed by the magnets used in the torch 'of the invention.

, Referring now to Fig. 1 of the drawing, the electric welding" torch there illustrated comprises a supporting member or handle l0, preferably of suitable insulating material, such as vulcanized fibre, Bakelite, or the like, to one end of which there is fixed a shield II which may be of similar material. Supported from the handle III are a pair of longitudinally extending rods l2 and I3, the'rod l2 being rigidly secured in the handle ID as by driving it into a force fit in the recess Illa. In the preferred arrangement illustrated, therods l2 and I3 lie in a plane normally substantially parallel to the palm of the hand of the user.' The rod l3 may be tubular in form, having a solid extension l3a with a portion l3b of reduced section driven into the end of the tubular portion. The extension I3a is longitudinally adjustable within the handle I 0, sliding in bushings l5 and I6 secured at opposite ends of the handle l0 and carrying a. guide I sliding on the fixed rod l2. The rod I3 is threaded over a portion of its length, as indicated at I30, and co-operates with a thumb nut l1 disposed thereon and movable in a recess lb of the handle member III. The thumb nut I1 is biased by a coil spring I8, or equivalent, to one extreme position in which the electrodes of the torch are in an inactive position. However, the thumb nut I 1 may be retained at an intermediate position in the recess lllb, corresponding to an operating position of the electrodes, by means of a spring finger or latch l9 secured to the handle I.

On the ends of the rods l2 and I3 remote from the handle III are rigidly secured the electrode holders 26 and 2t,

.tively, in an ofiset trical connections.

a circuit thus extends respectively, adapted to hold a pair of welding electrodes 22 and 23, respectively, preferably carbon electrodes, in arc-forming position, the holder 2i being suitably insulated from rod id. The electrode holders 2G and El hold the electrodes 22 and 23, respectrodes normally lie substantially in a plane parallel to that including the supporting rods l2 and i3 and at an angle to each other preferably less than 90 degrees and between 25 degrees and 75 degrees, an angle of about 35 degrees having been found particularly advantageous.

The electrical connection to the electrode 22 is made through a conductor 25% disposed within the rod i2, which is preferably'oi tubular form, and insulated therefrom, this conductor extending fom the handle at in a projection 2130. forming a suitable electrical terminal. The electrical circuit for the electrode 23 extends through the rod 83 which may be a tube of conductive material and thus, itself, form one of the elec- At the-handle end of the rod 53, an extension i311 of. the conductor l3a forms the other electrical terminal for the torch. While any suitable connections maybe made to the type of connector. comprises a conductive tube or sleeve 50 having one or more longitudinal slots 40a, suitable supply lines dill) being soldered in the unslotted ends. This type of construction avoids the tendency of the conventional split prongs to break ofi in use.

Disposed within the angle between the electrodes 22 and 23 is an electromagnet 26 supported from the electrode holder 20 and provided with a winding 21 comprising a relatively few turns of heavy insulated wire. Disposed position so that these elec-' terminals B11 and 2611, a preferred In. operation it will be assumed that, initially, the latch i9 is withdrawn so that the spring 88 biases the thumb nut H to the extreme righthand position, in which position the electrodes 22 and 23 are separated by such a distance that no arc is formed between them. If the terminals 2M and 5311 are then connected to a suitable source of welding current and the thumb nut H is actuated by the operator to its extreme left-hand position momentarily touching the electrodes 22 and 23 to strike an arc and then released against the latch 59, a working arc will be formed between the electrodes 22 and 23. If this are is not of the proper intensity for the work at hand, the relative positions of the electrodes 22 and 23 may be adjusted by the thumb nut H to shorten or lengthen the arc. With any suitable adjustment, the field of the electromagnet 26 is such as to extend the arc away from the welding torch, while the fields of the electromagnets 28 and 3B are such as to concentrate the arc toward a point. Adjustment of the electrodes 22 and 23 to adjust the length of the are generally effects a change in the value of the welding current. Since the windings of the electromagnets 2E, 28,'and 30 are in series with the welding current, the extending and concentrating fields vary with the welding current and are thus efiective to maintain a substantially uniform and stable arc.

The nature of nets 26, 28, and 30 is represented schematically in Fig. 3a, while an alternative arrangement of magnets requiring only two electromagnets and t the fields developed thereby are schematically outside of the angle of the electrodes 22 and 23, and at either side thereof, are the electromagnets 28 and 30 having windings 29 and 3!, respectively, also formed of a few turns of relatively heavy insulated wire and forming the support for the electromagnets. Suitable terminals 32, 33, 34, and are provided for the windings 21, 29, and 3|.

from the terminal 240. through the conductor 24, the winding 29 of electromagnet 28, the winding 21 of electromagnet 26 to the electrode holder 20, thence to the electrode 22 through the arc} the electrode 23, the electrode holder 2!, the windin 3| of electromagnet 30, to the supporting rod l3, and thence to the other terminal 1311. It is thus .seen that magnets 26, 28, and 30 are all in series with the arc current so that the magnetic fields developed thereby are at to the arc current. The magnet26 is designed to have a magnetomotive force approximately ghree times that of each of the magnets 28 and While each of the electromagnets 26, 28, and 30 may be constructed in any suitable form, the preferred structurevis shown in cross-sectional detail in-Fig. 2, from which it is seen that each of the electromagnets comprises a magnetic core consisting of a stack of U-shaped laminations with the angle a between the legsv of the U approximately degrees. These U-shaped magnets are so mounted that they efiectively bridge the arc, having a common plane of symmetry substantially coincident with the plane including the two electrodes in their normal position.

The complete electrical the windings of the electroconnected to the negative terminal.

all times proportional elements not requiring represented in Fig. 3b.

It has been found that in one embodiment of an electric welding torch in accordance with the invention, the arc was well formed for extensions of the electrodes of some inch to 2 inches beyond the poles of the magnets, thus permitting operation of the torch for a considerable interval during which some 2 inches of the electrodes may be consumed without are-adjustment of In case the welding torch is to be used for alternating current welding, ithas been found preferable to make both electrode carbons of the same size. If the torch is to be used for direct current welding, it has been found preferable to make the electrode connected to the positive terminal of a. larger diameter than that In a particular welding torch, electrodes of some inch to /2 inch and inch to inch have been used as positive and negative electrodes, respectively. If the welding torch is to be used exclusively for direct current welding, it will be understood that the electromagnets 26, 28, and 30 may be replaced by suitable direct current laminated cores, or by the electrodes.

permanent magnets.

While there has been described what is k at present considered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore.

aimed in the appended claims to cover all su h changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. An'electric welding torch comprising, a supporting member, a pair of electrode holders supthe field developed by the magported thereby and adapted to hold a pair of current-carrying electrodes at an angle to each other and in arc-forming position, a first magnet disposed within the angle of the normal electrode positions for forming a magnetic field transverse to the normal path of the arc to extend it away from the torch, and a pair of magnets disposed on opposite sides of said normal electrode positions at an angle of less than 180 degrees and including said normal electrode positions for developing a magnetic field in the region of the arc to concentrate the arc into substantially a point.

2. An electric welding torch comprising, a supporting member, a pair of electrode holders supported thereby and adapted to hold a pair of current-carrying electrodes at an angle to each other and in arc-forming position, a first magnet disposed within the angle of the normal electrode positions for forming a magnetic field transverse to the 'normal path of the arc to extend it away from the torch, ,and a pair of magnets disposed on opposite sides of said normal electrode positions at an angle or less than 180 degrees and including said normal electrode positions for developing a magnetic field in the region of the arc to concentrate the are into substantially a point, said magnets and said normal electrode positions having a common plane of symmetry.

3. An electric welding torch comprising, a supporting member, a pair of electrode holders supported thereby and adapted to hold a pair of current-carrying electrodes at an angle to each other and in arc-forming position, a U-shaped magnet disposed within the angle of the normal electrode positions for forming a magnetic field transverse to the normal path of the arc to extend it away from the torch, and a pair of U-s haped magnets disposed on opposite sides of said normal electrode positions at an angle of less than 180 degrees and including said normal electrode positions for developing a magnetic field in the region of the are to concentrate the arc intosubstantially a point, the open ends of the Us of said magnets racing the normal arc path and Us lying substantially in planes transverse to the normal arc Path.

4. An electric welding torch comprising, a supporting member, a pair of electrode holders supported thereby and adapted to hold a pair of current-carrying electrodes at an angle to each other and in arc-forming position, a first magnetic means-disposed within the angle of the normal electrode positions for forming a mag netic field transverse to the normal path of the arc to extend it away from the torch, a pair of magnets disposed on opposite sides of said normal electrode positions at an angle of less than degrees and including said normal electrode positions for developing a magnetic field in the,

region of the arc to concentrate the are into substantially a point, and means for controlling the field of said magnetic means in accordance with the arc current.

5. An electric welding torch comprising, a supporting member, a pair of electrode holders supported thereby and adapted to hold a pair of ourrent-carrying electrodes at an angle to each other and in arc-forming position, a first magnet disposed within the angle of the normal electrode positions for forming a magnetic field transverse to the normal path of the arc to extend it away from the torch, and a pair of magnets disposed on opposite sides of said normal electrode positions at an angle of less than 180 degrees and including said normal electrode positions for developing a magnetic field in the region of the arc to concentrate the are into substantially a point, said first magnet having a magnetomotive force of the order or three times that of'each of said pair of magnets.

1 BURTON L. CASNER. 

